Means for transferring heat to or from material on band conveyors



Much 9, w48. W H, ALLEN 2,437,492

MEANS FOR TRANSFERRINQ HEAT TO OR FROM MATERIAL ON BAND CONVEYORS FiledMarch 22, 1945 s sheets-'sheet 1 |NVENTOR Wal l'er H. Allen T ORN EYS w.H. ALLEN 2,437,492

MEANS FOR TRANSFERRING HEAT TO OR FROM MATERIAL ON BAND CONVEYORS FiledMarch 22, 1945 3 Sheets-Sheet 2 mvsmon la/aller Alle BYLQWL Max'ch 9,1948.

MEANS FOR TRANSFERRING HEAT TO OR FROM MATERIAL ON BAND CONVEYORS 3Sheets-Sheet 3 Filed March 22 lNVENTOR Walier Allen MUQS AT QRNEYS D.. 4In .k

Patented Mar. 9, 1948 OFFICE MEANS FOR TRANSFERRING HEAT TO R FROMMATERIAL ON BAND CONVEYORS Walter Harvey Allen, Birmingham, England, as-

sgnor to Sandvik Steel Incorporated, New

York, N. Y.

Application March 22, 1945, Serial No. 584,218 In Great Britain March25, 1944 1 Claim. 1

This invention relates to a means for transferring heat to or frommaterial carried upon a band conveyor. The invention is especiallysuitable for cooling plastic, uid or other substances and forsclidifying or crystallising such substances as are capable of beingsolidified or crystallised by the abstraction of heat therefrom.

The object of the invention is to provide an improved method of andmeans for transferring heat from material carried upon a band conveyor,for cooling the material, whereby the heat transfer is eifected quicklyand in a uniform 4and eiiicient manner.

According to the invention, a method of transferring heat from materialconsists in carrying said material upon an endless conveyor band passingaround terminal drums having horizontal axes, and causing the saidconveyor band to move over and to rest or float directly upon the uppersurface of cooling or heating liquid within a tank or trough disposedbeneath a strand of the band that carries the material.

Also, according to the invention, a method of cooling material consistsin carrying said material upon an endless conveyor band passing aroundterminal drums having horizontal axes, and causing the said conveyorband to move over and to rest or float directly upon the upper surfaceof cooling liquid which is circulating through a tank or trough disposedbeneath a strand of the band that carries the material. A plurality ofsuccessive tanks or troughs may be provided respectively containingcooling liquid at different temperatures.

Means for transferring heat from material carried upon a band conveyor,according to the invention, comprises, in combination With an endlessconveyor band passing around terminal drums having horizontal axes, oneor more tanks or troughs disposed beneath the top strand of the band andadapted to be filled with a cooling or heating liquid up to theunderside of the band so that the said underside travels in directcontact with and floats upon the upper surface of said liquid. l

The conveyor' band may be supported upon longitudinal slide bars carriedupon the tank or trough. Side overilow compartments or channels may beprovided into which cooling liquid overiiows from the one or more tanksor troughs, said compartments or channels having outlets for thedischarge of the liquid.

The forced circulation of cooling liquid through the one or more tanksor troughs may be effected by means of longitudinal perforated pipes insaid 2 tanks or troughs and through which liquid is forced by a pump.

Figure 1 of the accompanying drawings is a side elevation, partly insection, of one example of cooling apparatus according to the invention.This particular apparatus shown is suitable for cooling pitch or similarproducts, and may be modied to suit other substances.

Figure 2 is a plan, with a portion of the conveyor band broken away, ofa small portion of the apparatusr showing the cooling tank in plan andconvenient means for admitting the cooling liquid.

Figure 3 is a cross-section, on a larger scale than Figure 1, upon lineIII-III, Figure 1.

Figure 4 is a corresponding cross-section on line IV-IV, Figure l.

Figure 5 is a side elevation of a. modified form of apparatus havingprovision for effecting the cooling in successive stages at dilerenttemperatures.

Figure 6 is a cross-section through the conveyor band and tank.

Figure '7 is a cross-section on line VIL-V11, Fig ure 5, showing theside retaining bands that may be used.

Referring to Figures 1 to 4 of the said drawings.v

which show one example of the invention which is suitable in connectionwith the continuous cooling, solidifying or crystallising of hot uid orplastic material, the apparatus comprises a band conveyor consisting ofan endless steel or other heat-conducting band l disposed horizontallyand running around terminal drums 2, 3, mounted upon a frame 4, one ofwhich drums is suitably driven, as from an electric motor operatingthrough reduction and speed-varying gear. Above the charge end of theconveyor is an inclined plane or feed chute 5 from which the material isdeposited upon the top surface of the band so that it spreads out toform a thin uniform layer that is continuously carried along by theband; but it is to be understood that any other means for feeding thematerial on to the band maybe employed.

Mounted upon the conveyor frame 4, beneath substantially the full lengthof the top strand of the band, is a longitudinal main tank or trough 6adapted to contain'a large body of water or other cooling liquid whichis maintained in continuous circulation as hereinafter described. Thismain tank 6 has a width equal to nearly the full Width of the band, andon opposite sides thereof are longitudinal overflow compartments orchannels 1, 1, having suitable outlets 1'. The side walls of the maintank have fixed to their upper portions vertically-disposed narrowlongitudinal brass or other suitable slide bars 8 which project abovesaid side walls and upon the top edges of which the band I is directlysupported. and travels. Water or other cooling liquid is continuouslyadmitted to the main tank 6 through an inlet I0 and thus maintains thelatter full, with the band directly resting or iloating upon the surfaceof the liquid between the slide bars, thus abstracting heat from theband and from the material thereon and progressively cooling thelatter.. As cooling liquid continues to enter the tank, liquid overiiowsbetween the band I and the slide bars 8 into the side compartments orchannels 1, and thence it is discharged through the outlet. v Y

Conveniently the cooling liquid is supplied to the tank through one, twoor more longitudinal perforated pipes, such as.9, 9, lying upon thebottom of the tank and from the holes 9 in which the liquid is directedupwards in oblique directions towards the band. These pipes may be intwo longitudinal sections, those of each section being connectedtogether near the middle of the length of the tank and the two sectionsbeing connected to a common inlet pipe I through which the liquid issupplied from a pump (see Figure 2). This Acommon inlet pipe I 0 may,when dealing with a material that is insoluble and non-absorbent, alsosupply cooling liquid to a longitudinal overhead spraying pipe IImounted on the conveyor frame above the band so as to spray liquid ontothe material to give asecondary cooling effect. This secondary coolingpipe may extend for any suitable length of the band, but when fumes areliable to be evolved from the hot material, as in the case of pitch, thefirst section of the band from the charge end may be enclosed Within atunnel or casing I2 constituting an air duct at one end of which is amotor-'driven fan I3 which causes a current of air to traverse the duct.This air stream carries away the fumes through a suitable outlet I4 andalso helps to cool the material. If desired, an air duct o f thischaracter may extend for the full length of the band with or without theoverhead spraying pipe.

As there is a large body of water in the main tank which is in directcontact with the underside vofthe band and which is also in -constantcirculation, a very effective exchange of 1 heat takes place between theband and the water, resulting in a rapid continuouscooling of thematerial on the band as it is carried forward towards thegdischarge endof the band where it may break off by its own weight or may be removed'by a scraper or the like.

The modification represented in Figures 5 to 7 is suitable for use withmaterials having a high fluid content, such as gelatine, for example,the cooling being effected in several different stages at differenttemperatures, and provision being made for conning it laterally upon theband whilst in a liquid state. Thus, the liquid material may be'fed rston t0 an inclined water-cooled tray Ida or any other form of pre-coolerlocated above the charge end of the band I,being delivered from thispre-cooler on to a deiiector plate I5 and thence on to the band where,foi` a certain length of the said band, the material may be coniinedlaterally between'rubber or other side bands,

chainsV or other endless iiexible members I6 running over pulleys I1 anddriven by frictional contact with the conveyor band I so that said bandand exible members- I6 travel at the same velocity. The cooling of thematerial whilst travelling upon the band may be effected by one, two ormore separate tanks or troughs located beneath the top strand of theband and through which cooling liquid is circulated in direct contactwith the band as hereinbefore described, the liquid in the differenttanks (if more than one) being at different temperatures. Thus, in theparticular example shown, two tanks 6, (ia used. The iirst of thesetanks 6 may extend for about one half the length of theband from thecharge end, and gives a normal cooling. The second tank 6 extends forthe remainder of the length of the band and may be designed to give alow temperature cooling, the cooling liquid being below the freezingpoint .of water. Side overflow compartments or channels 'I may beprovided as in Figures 1 to 4, the cooling liquid being circulated bypipes 9. In this apparatus an air duct I8 may be provided above theentire length of the band, with means for causing a current of cold airto pass therethrough. The order of cooling in the different tanks may bevaried as may be desired. For example, a loW temperature cooling mayprecede cooling at a higher temperature.

If desired, there may be three slide bars 8, one

along the middle of the tank, mid-way between those xed to the sidewalls, being designed to support the middle portion of the band andbeing secured in any suitable manner.

I claim: l

An apparatus for cooling material carried upon a horizontal strand of anendless metal conveyor band, said apparatus comprising a vesselextending longitudinally beneath said strand and being of substantialdepth throughout its length and width, said vessel having a flat bottomand upstanding side walls extending to said strand, a plurality oflaterally spaced apertured pipes disposed within said vessel onthebottom thereof and extending longitudinally throughout substantially theentire length of the vessel, and means maintaining a continuous forcedcirculation of cooling liquid through said pipes and vessel and causingsaid liquid to maintain a normal level which is such that the undersideof the band is in contact with the liquid and that the liquid overflowsthe top edges of the side wall, whereby said strand oats on the liquidand whereby jets of liquid from the apertured pipes pass through theliquid and are thoroughly mixed with the liquid already contained in thevessel before they reach said strand.

WALTER HARVEY ALLEN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 810,864 Hoover et al. Jan. 23,1906 1,869,232 Weiland July 26, 1923 2,006,919 Haug July 2, 19352,015,168 Varney Sept. 24, 1935 2,094,785 Flint Oct. 5, 1937 2,286,225Noyes June 16, 1942 2,360,100 Bowen Oct. 10, 1944

